The invention concerns a method and apparatus for controlling the operation of an internal combustion engine, and in particular, to a method and apparatus for controlling the combustion process of an externally ignited internal combustion engine.
Different procedures exist to influence the combustion process of externally ignited combustion engines containing at least one combustion chamber with at least one reciprocating or rotating piston. It is an established fact that ignition settings and/or the composition of the combustion charge, i.e., air-fuel ratio of the charge, may be altered in accordance with selected operating parameters, such as, for instance, engines revolutions, outside temperature, barometric pressure, temperature of the cooling water, temperature of the lubricating oil, temperature of the fresh charge and the oxygen content of the exhaust gas. It is also an established fact that knock or detonation sensors can be installed in an internal combustion engine which detect detonation and accordingly alter the ignition setting to elminate the detonation. The aquisition of these parameters and the necessary procedures to alter the ignition setting and/or the composition of the combustion charge do not necessarily guarantee the maintenance of the initial thermal efficiency during long time operation. Rather, on the contrary, due to uncontrolled foreign influences, the initial ignition setting is altered unfavorably during operation. In addition to this situation, if many parameters are sensed and utilized to obtain the ignition setting, the tuning of these parameters to each other can be complicated and time consuming. Furthermore, the existing methods which independently alter the ignition settings cannot take into account all the parameters which really influence the combustion process, i.e., the composition of the actual fuel, the deposits accumulated in the combustion chamber after a certain period of time, the inside temperature of the combustion chamber, and the instantaneous setting of the carburator, etc.